Control circuit for signal recording and reproducing systems



Feb. 24, 1953 5, J, BEGUM 2,629,861

CONTROL. CIRCUIT FOR SIGNAL RECORDING AND REPRODUCING SYSTEMS Original Filed Nov. 29, 1944 FL/45 gr/4 v la 6o Qf ATT/vz/ATo/?- 61 AMPLIFIER Egg I AMPLIFIER LE VEL' 47 NETWORK K SIGNAL SOURCE RECTIFIER SEMI JOSEPH BEGUN ATTORNEY Patented Feb. 24, 1953 'GUNT'BD C R UI FO SIGNAL RECORD- ING AND REPRODUCING SYSTEMS Semi Joseph Begun, Cleveland Heights, Ohio, as-

iiznor to The Brush DevelopmentCompany,

Cleveland, Ohio, a corporation of Ohio Original "application NoveniberZS, 1944, Serial No. 565,736. Divided and this'ap'plication October 11, 1947,-Serial No. 779,238

7 Claims. 1

This invention pertains to control circuits for use in signal recording and reproducing systems such for example as those "embodying magnetic, optic or mechanical transducer means.

This applicationis a division of 'my application Serial Number 565,736, filed November 29, 1944 for a Control Circuit -for'a Signal Recording and Reproducing System, which issuedas Patent No. 2,439,446 on-April 13, 1948, which is assigned 'to the same assignee as the present invention.

-It is often desirable very rapidly to measure long lengths of materials with a reasonable degree of accuracy. The present invention provides measuring means which can be driven in-synchro- -nism with or by the same drive system as the materials to be measured, and the measuring means indicates the total'amount of the material which passes a certain point. The material to be measured may be wound fromone reel onto another reel without introducing "error due to the variable diameter of the reels. 'Alsmthe speed of the drive system may be varied without introducing error into the measurement.

An object of the invention is to provide a controlcircuit for a-signal recording andreproducing system'wherein the reproducing circuit exercises a function on the recording-circuit.

Another object of the invention is to provide a control circuit for a signal recording and reproducing system wherein'one or more conditions of the recordingcircuit may be'varied in accordancewith one ormore conditions of the reproducing circuit. V v

In'accordance with'this invention there is provided a signal recording and reproducing system which comprisesa record member" and signal recording means, including'iir'st andsecond signal input circuits, for recording on-the record member. Signal'reproducin'g means are'provided for reproducing the signal from the record member. Means areprovided which effect-relative motion between the record member and both of the above-mentioned means. Signal altering means are connected alternatively to each of the input circuits and there is a control circuit connection from the reproducing means to the signal altering means for alternatively connecting each input circuit to the recording means in accordance with the signal reproduced from the record memher.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accom- .panying drawings, and its scope will be pointed out in the appended claims.

In the drawings, Fig. 1 is a simplified-schematic diagram of one embodiment of the invention, and Fig. 2 is a block diagram of a different embodiment of the invention.

In the system shown in Fig. 1, two oscillators 35, 36.,generating different frequencies are provided and either of them supplies current to the recording head 31in accordance with a time sequence controlled by the reproducing circuit which actuates a switch 42' located in the recording circuit. In one-position of theswitch 42, the oscillator 35 is connected to the recording head 31 and, in the other position, the oscillator 36 is connected to the recording head 31.

The output from the pickup head 38 .is amplified by the amplifier 39 and the amplified output is-supplied to the input of a filter 40 which passes signals of a frequencyfi butrejects signals ofa frequency f2.

The signal of one frequency which passes through the filter 40 is used, after recification by the rectifier 4|,to control a relay 42. Therelay 42 actuates switch 42' to cause it alternately to connect first the oscillator 35 and then the oscillator 36'to'the recording head 31.

-In another form of the invention, shown in Fig. 2, the recording head '43 is supplied from one or more signal sources 44 with signals of difierentintensity levels. One side of the circuit from the signal source 44 to therecording head 43 includes an attenuator and,1in parallel with the attenuator '60, there is a circuit including a switch 45'. The output 'from the reproducing head 46, whichpi'cks up'the'signal recorded on the record member), is amplified by an amplifier 39. The amplified signal passes through 'a network 41 which passes only signals of an undesirably high intensity 'to'a rectifier 4|, such 'as those signals which overload the record member Ill. The outlputirom the rectifier is connected to the relay '45 which opens the switch 45' in the recording When the intensity of the signal being reproduced from the record member reaches an intensity approaching saturation, the level network 41, depending upon its setting, passes current to the rectifier 4| and the output therefrom energizes the solenoid 45 causing it to open switch 45. This reduces the level of the signal being recorded, as has been explained, and simultaneously through the mechanical or electrical connection GI increases the gain of the amplifier 62 to make up for the reduced level of the recorded signal.

The reproducing head 46 is an appreciable dis tance away from the recording head 43. This introduces a time delay T in the actuation of the switch 45 after the actuating signal was recorded on the record member. T is a function of the distance between the heads 43 and '46 and the rate of motion of the record 10. To reduce this delay T to a minimum, the reproducing head 46 should be positioned close to the recording head 43 and, to reduce the eifect still further, a time delay equal to T in duration may be introduced between the actuation of the solenoid 45 and the changing of the gain control 6|. When the level of the signal source, after attenuation, drops to such an extent that the signal impressed upon the signal carrier l0 reduces the signal-to- -noise ratio in an undesirable manner, the natfications may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes 'and modifications as fall within the true spirit and scope of the invention. 4

I claim:

1. A signal recording and reproducing system comprising: a record member, signal recording means for recording on said record member and including first and second signal input circuits, signal reproducing means for reproducing the recorded signal from said record member, means for efiecting relative motion between said record member and both of said above-mentioned means, signal altering means connected alternatively to each of said signal input circuits, and a control circuit connection from said signal reproducing means to said signal altering means for alternatively connecting each signal input circuit to said recording means in accordance with the signal reproduced from said record member.

2. A signal recording and reproducing system in accordance with claim 1 in which said signal altering means is a switch for opening the first signal input circuit and substantially simultaneously closing the second signal input circuit.

3. A signal recording and reproducingsystem in accordance with claim 1 in which said signal altering means is a. signal attenuator which alters the intensity 0! both of the signals supplied to said recording means.

4. A signal recording and reproducing system in accordance with claim 1 in which said first and second signal input circuits include two sources of signal one in each circuit only one of which is connected to said recording means at a given instant and said signal altering means is a switch which breaks a connection from said one of said signal sources to said recording means and connects the other of said signal sources to said recording means when the said signal reproducing means reproduces a recorded signal.

5. A signal recording and reproducing system comprising: a magnetizable record member, a magnetic signal recording head in flux-linkage relationship with said magnetizable record member, two signal input circuits connected to said magnetic recording head, a magnetic signal reproducing head in flux-linkage relationship with said magnetizable record member, a signal output circuit connected to said magnetic reproducing head, driving means for effecting relative motion between said magnetizable record member and said heads, signal altering means connected alternatively to each of the said signal input circuits, and a control circuit connection from said signal output circuit to said signal altering means for alternatively connecting each signal input circuit to said magnetic recording head in ac- -cordance with the signal reproduced from said magnetizable record member by said magnetic reproducing head.

6. A signal recording and reproducing system as set forth in claim 5, further characterized by said mangetizable record member comprising an endless magnetizable body, and by said driving means/moving said record member in a direction from said recording head to said reproducing head.

'7. A signal recording and reproducing system as set forth in claim 6, further characterized by said signal altering means comprising switch means for closing one of said signal input circuits and opening the other during the recording of a signal on said record member, said signal altering means operating upon the reproduction of said recorded signal to throw said switch means to open said closed circuit and close said open circuit.

- SEMI JOSEPH BEGUN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,338,766 Holcomb Jan. 11, 1944 2,385,701 Halstead Sept. 25, 1945 

